title: Temporal trends in dioxins (polychlorinated dibenzo-p-dioxin and dibenzofurans) and dioxin-like polychlorinated biphenyls in Baltic herring (Clupea harengus).
abstract: Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyl (dl-PCBs) concentrations in Baltic herring (Clupea harengus) have been relatively stable since the mid to late 1990s. It is unclear why concentrations in Baltic herring are not following the observed decreases in other environmental matrices. Here, changes in long-term temporal trends in Baltic herring were examined. A number of biological variables were examined alongside the temporal trends to investigate whether fish biology e.g., growth (length, weight, age), lipid content, reproductive phase or fishing date may provide an explanation for the temporal trends observed. Significant (p<0.05) decreasing trends were observed for PCDD/F toxic equivalents (TEQPCDD/F) at three of the four sites (lipid weight (lw) and wet weight (ww), Swedish west coast lw only); however, other TEQ values e.g., TEQPCDD, TEQPCDF, TEQdl-PCB, TEQPCDD/F+dl-PCB were inconsistent, decreasing at some sites but not others. In the most recent 10 years of data, fewer significant decreases were seen overall. Over the examined time period, significant decreases (Bothnian Bay, p<0.01, southern Baltic Proper, p<0.02) and increases (Swedish west coast, p<0.02) in lipid content, growth dilution or lack thereof, and significant changes in age were observed. However herring were not randomly selected which biases this result. Continual efforts to decrease PCDD/F and dl-PCB emissions and to locate/reduce hotspots are necessary, while bearing in mind that herring biology may be impeding faster decreases of these chemicals.
authors.affiliation: Department of Environmental Research and Monitoring, Swedish Museum of Natural History, P.O. Box 50 007, SE-104 05 Stockholm, Sweden. Aroha.Miller@nrm.se
authors.forename: Aroha
authors.initials: A
authors.lastname: Miller
authors.forename: Jenny E
authors.initials: JE
authors.lastname: Hedman
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Nyberg
authors.forename: Peter
authors.initials: P
authors.lastname: Haglund
authors.forename: Ian T
authors.initials: IT
authors.lastname: Cousins
authors.forename: Karin
authors.initials: K
authors.lastname: Wiberg
authors.forename: Anders
authors.initials: A
authors.lastname: Bignert
mesh_terms: D000818:Animals; D001572:Benzofurans / Q000378:metabolism*; D000072338:Dibenzofurans, Polychlorinated; D004147:Dioxins / Q000378:metabolism*; D004784:Environmental Monitoring; D005399:Fishes / Q000378:metabolism*; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data
chemical_list: D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D004147:Dioxins; D000072317:Polychlorinated Dibenzodioxins; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls
keywords: Baltic Sea; Baltic herring; Dibenzofurans; Dioxin-like polychlorinated biphenyls; Polychlorinated dibenzo-p-dioxins; Temporal trends